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A polyhedrosis virus was found in collections of Bruce spanworm, Operophtera bruceata(Hulst), larvae from two locations in British Columbia in 1957 (O. N. Morris, pers. comm.). Bruce spanworm was prevalent in the Maritime Provinces and Quebec in 1963 and 1964 and a polyhedrosis virus was credited with terminating this outbreak (Forbes et al.1964, 1965; Martineau 1964, 1965). A detailed examination of the virus from Quebec showed that it was a singly-embedded (unicapsid) nuclear polyhedrosis virus (Smirnoff 1964) which is classified as Baculovirussubgroup A (Matthews 1979).

AbstractDuring 1972, spruce budworm infested white spruce and balsam fir trees were sprayed aerially with a low dose of fenitrothion (0.25 oz AI/ac), entomopox virus (EPV) at 7.6 ? 1010polyhedra/ac, nuclear polyhedrosis virus (NPV) at 2.7 ? 1011polyhedra/ac, or each virus?fenitrothion combination. Fenitrothion (active ingredient), NPV, and EPV deposited at ground level at 5%, 31%, and 42%, respectively, of the amounts emitted.In the year of application, NPV + fenitrothion was highly effective in population reduction and foliage protection especially on; balsam fir although a higher virus infection rate was found on white spruce than on balsam fir. EPV + fenitrothion also provided a high level of foliage protection and apparently reduced surviving female:male sex ratio to 1:2 compared with the normal 1:1 ratio. NPV + insecticide caused highest larval mortality, highest incidence of virus, lowest rate of moth emergence, fewest progeny, and lowest rate of progeny survival. The natural incidence of microsporidia was low in all plots.In the year following application, the NPV + insecticide treated plot again showed lowest population density, highest larval mortality and incidence of virus, and low defoliation and egg mass density. However, there was a higher proportion of viable eggs deposited than in the previous year. Egg parasitism by Trichogramma minutumincreased by 1.5 to 4.2% in plots treated with virus only and declined by 1.6 to 10.5% in insecticide treated plots and by 1.2% in untreated check plot. The transmission of the virus from one year to the next is considered to be of paramount importance in the future use of this pathogen in spruce budworm control.

AbstractTwo different application methods were tested using a nuclear polyhedrosis virus as a control agent at an early stage in the outbreak cycle of Douglas-fir tussock moth, Orgyia pseudotsugata(McDunnough), in south central British Columbia in 1981. The virus, which often leads to the development of an epizootic late in the outbreak cycle, was propagated in whitemarked tussock moth, Orgyia leucostigma(J. E. Smith). A helicopter fitted with a boom and nozzle was used for treating four plots (total area 19.8 ha) at a dosage of 2.2 ? 1011polyhedral inclusion bodies (PIB) in an emitted volume of 11.3 L ha?1. Five to eight weeks after spraying, microscopic examination of live larvae showed that 77 to 100% were infected. In ground-spray applications of two other plots, a modified orchard-type sprayer was used to apply 2.4 ? 1010PIB in a volume of 4.5 L per tree. Microscopic diagnosis of live larvae at 8 weeks post-spray revealed 83 and 85% infection.In autumn 1981, no egg masses could be found in the plots treated earlier that year and no larvae were found on the sample trees in 1982 or 1983. The treatment was effective over a range of initial mean larval densities of 41 to 206 m?2of foliage. At the same time, populations in nearby untreated areas increased in 1982. Little foliage protection was obtained the year of application due to the lengthy virus incubation period, but the trees recovered quickly when populations disappeared due to the virus epizootic.

AbstractLarvae of the eastern hemlock looper, Lambdina fiscellaria fiscellaria(Guen.), are susceptible to a nuclear polyhedrosis virus as well as nuclear polyhedrosis viruses isolated from the western hemlock looper, L. f. lugubrosa(Hulst), and the western oak looper, L. f. somniaria(Hulst). The pathogenicity of these viruses was similar when tested on eastern hemlock looper larvae and it is suggested that the same virus infects the three subspecies. Resistance to the virus did not increase with age; second-, third-, and fourth-instar larvae were equally susceptible. The period from ingestion to death varied with concentration of virus and rearing temperature. Results of pathogenicity tests are given.

AbstractA previously undescribed entomopoxvirus was isolated from larvae of Choristoneura conflictanaWlk. Samples of larvae taken from several points in Ontario indicated that the virus was widespread in the Province.The morphology of the virus is described. The inclusion bodies are larger than those of another entomopoxvirus originally isolated from Choristoneura biennisFree. and propogated in Choristoneura fumiferana(Clem.). The virions are of the same order of size for both viruses. Microspindles are associated with these viruses and some of the spindles are occluded along with the virions within the oval inclusion bodies. The C. conflictanaentomopoxvirus is also infectious to C. fumiferana.

Presents letters to the editor referencing various articles and topics published in the previous issues. "Houses Sunny-Side Up," which focused on garden cities of France; Reader's response to an article on Eskimo dogs; Discussion of the U.S. aid to Europe for economic development.

Western false hemlock looper, Nepytia freemaniMunroe, is a cyclical pest in British Columbia which defoliates mainly Douglas-fir, Pseudotsugata menziesii(Mirb.) Franco, often near residential areas. Outbreaks were recorded from 1947 to 1949, 1963 to 1964, and 1972 to 1976; the current outbreak started in 1980 and, in 1982, covered 1,100 ha near Tappen, Canoe, Enderby, and Carquile (Ferris and Woensdregt 1983).

Presents several letters to the editor on issues related to the United States politics. Inhuman acts on Haitians by the American military; Doubts about the legitimacy of the work of the Russian Red Cross in the United States; Appreciation of the loyalty shown by the colored voters to the Republicans.

An understanding of all environmental effects resulting from control actions is important in the selection of a method of managing insect populations. Effects may extend beyond the year of treatment and can modify management decisions. In 1978, a nuclear polyhedrosis virus (NPV) and Bacillus thuringiensisBerliner (B.t.) were tested as aerial spray applications against the western spruce budworm, Choristoneura occidentalisFreeman, on Douglas-fir, Pseudotsuga menziesii(Mirb.) Franco, near Cache Creek, British Columbia. The impact on population densities and on the incidence of NPV was measured in the treated and non-treated areas for 2 vears following the year of application, and is reported here.